Just noticed something interesting, you can subscribe to any #YouTube channel through #Friendica. This is really useful, partly because YouTube's own really awful subscription system doesn't show the latest uploads :P
Here's what you do:
1. Go to the uploads page for the YouTube channel you want to subscribe to, and copy the URL
2. Go to your Friendica contacts page and paste the YouTube channel's URL into "Add New Contact", then click "Connect".
3. Confirm the connection and then wait a while so the feed can get established.
Note: This may not work on all channels, it seems to have trouble with those whose URL is a very long strings of letters and numbers.
It seems to work because the YT channel URL turns into an #RSS feed when you enter it into a feed reader, such as Friendica.